1. Field of the Disclosure
Embodiments disclosed herein relate generally to systems and methods of processing hydrocarbon laden solid sources. More specifically, embodiments disclosed herein relate to systems and methods of separating bitumen hydrocarbons from mined oil sand, rocks, and clay. More specifically still, embodiments disclosed herein relate to systems and methods of separating bitumen hydrocarbons from cuttings produced during drilling operations.
2. Background Art
Throughout the world, considerable oil reserves may be found locked in the form of tar/oil sand, also known as bitumen sand. Bitumen, which is a viscous hydrocarbon, is trapped between the grains of sand, clay, and water. Because the recovery of bitumen from the sand may provide an increasingly valuable commercial energy source, processes for extracting and refining bitumen have long been investigated.
One method for recovering tar sand is by mining. In these operations, surface or shallow oil sands are open pit mined. The cost of mining increases with the depth of burial of the formation. At some point, the amount of overburden and the cost of its removal becomes too great. These deeper deposits have recently begun to be exploited by drilling wells through the overburden. In some cases, the bitumen behaves as a fluid under reservoir conditions, and may flow into the well for production by conventional means. However, in other cases, the bitumen is either too viscous or is too solidified, and may not flow. To recover these deposits, steam or other heat sources may be introduced into the tar sand formation to liquefy the bitumen. Recently, a technique of drilling closely spaced horizontal wells that allow a controlled passage of steam therebetween has become popular. After months of steaming, the molten tar flows into collection wells for recovery. So-called Steam Assisted Gravity Drainage is one such technique.
In Alberta, the tar sands underlie a wide expanse of undeveloped and environmentally sensitive areas in the north of the province. Drilling wells inevitably creates large amounts tar sand cuttings. Currently, tarred cuttings must be hauled to either existing mining operations or permitted disposal sites. Therefore, processes that separate tar from sands at the drill site and allow delivery of sands clean enough for on-site disposal may reduce the cost of drilling.
Similar problems may occur when attempting to remove tar from drilled cuttings as those encountered when trying to recover tar from mined sand. However, when removing tar from drilled cuttings, surfactants, substances present in drilling fluid, and substances otherwise used to facilitate tar removed during the drilling process may contaminate the drilled cuttings. Such substances and surfactants may cause environmental concerns if not removed from the drilled cuttings prior to disposal.
Such processes as those mentioned above have not facilitated the efficient extraction of bitumen oil from oil sands. The aforementioned processes either haven't been adopted by the industry due to the fact that they substantially increase the cost of bitumen extraction, or have been adopted but result in high levels of hazardous waste product. Accordingly, there exists a need for a process that increases the production of bitumen oil from oil sand, while decreasing levels of hazardous waste and producing substantially cleaner sands.
In addition to mining oil sand, cuttings produced during drilling in locations containing oil sand may result in cuttings including sand, bitumen, and drilling fluid. Typically, such produced cuttings are stored in bins at the rig site, and blended with materials such as sawdust, prior to treatment at a centralized disposal facility. Further blending may allow the sand to be disposed or re-used, while blending with soil may allow for land disposal or use in the construction of roads and/or drilling pads.
Accordingly, there exists a need for systems and methods for separating hydrocarbons from oil sand and cuttings.